Why not create a separate file, called "navigation.php" and include it into all the files that need it:
navigation.php:
<?php
// site nav:
$navigation = '<a href="index.php">Home</a> ]:[
<a href="calender.php">Calander</a> ]:[
<a href="search.php">Search</a> ]:[
<a href="browse.php">Browse</a>';
?>
index.php, calender.php, search.php, browse, php, ETC...
<?php /* create regular HTML and include nav where needed */ ?>
<table width="500" border="0" cellspacing="0" align="center">
<tr>
<td bgcolor="cccccc" align="center">
<?php
// include nav
include_once('navigation.php');
// echo value
echo $navigation;
?>
</td>
</tr>